Sealants useful in aerospace and other applications must satisfy demanding mechanical, chemical, and environmental requirements. For example, it is desirable that aerospace sealants function over a temperature range such as from about −67° F. to about 360° F. Michael addition curing chemistries employing divinyl sulfone and sulfur-containing polymers have been shown to produce aerospace sealants having faster cure rates and enhanced performance including fuel resistance and thermal resistance. For example, in the systems disclosed in U.S. application Ser. No. 13/529,237, filed on Jun. 21, 2012, sulfur-containing polymer adducts such as polythioether adducts containing terminal Michael acceptor groups such as vinyl sulfone groups are reacted with a curing agent such as a thiol-terminated sulfur-containing polymer to form a cured composition. Application of Michael addition curing chemistries to sulfur-containing polymers not only results in cured sealants with faster cure rates and enhanced performance including fuel resistance and thermal resistance, but also provides a sealant with improved physical properties such as elongation.
Sulfone-containing polythioethers having one or more sulfone groups incorporated into the backbone of the polythioether are disclosed in U.S. application Ser. No. 13/883,827 filed on Mar. 15, 2013, which is incorporated by reference in its entirety.
Sulfur-containing polymers having improved adhesion to metal surfaces and that meet other performance requirements for use in aerospace and other applications are desired.